Flying fish, any of about 40 species of oceanic fishes of the family Exocoetidae (order Atheriniformes), found worldwide in warm waters and noted for their ability to fly. They are all small, attaining a maximum length of about 45 cm (18 inches), and have winglike, rigid fins and an unevenly forked tail. Some species, such as the widely distributed Exocoetus volitans, are two-winged, with only the pectoral fins enlarged; others, such as the California flying fish (Cheilopogon), are four-winged, with both the pectoral and pelvic (posterior) fins enlarged.

A flying fish does not fly, in the sense of flapping its wing-sized fins, but actually glides. The fish builds up speed underwater, swimming toward the surface with its fins folded tightly against its streamlined body. Upon breaking the surface, the fish spreads its enlarged fins and gains additional thrust from rapid beats of the still-submerged tail. When sufficient speed has been attained, the tail is lifted clear of the water and the fish is airborne, gliding a few feet above the surface at a speed of about 16 km/hr (10 miles per hour). The fish can make several consecutive glides, the tail propelling it up again each time it sinks back to the surface. The stronger fliers can span as much as 180 metres (600 feet) in a single glide, and compound glides, timed as long as 43 seconds, may cover 400 metres (1,300 feet).

Flight for these fishes is primarily a means of escaping predators. Flying fish can attain enough height to carry them onto the decks of ships in their waters, where their remains are frequently discovered at dawn.

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any member of the order Atheriniformes, containing 15 families of marine and freshwater spiny-finned fishes, including the flying fishes (see), needlefishes, silversides, and cyprinodonts. The last group, the Cyprinodontidae, is an abundant tropical and subtropical family that includes the guppies,...

...dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike...

Because it depends upon the presence of a horizontal air current, the flight of flying fish is more akin to soaring than to true flying. As a flying fish approaches the water surface, its pectoral and pelvic fins, which are analogous to the forelimbs and hind limbs of quadrupeds, are pressed along the side of the body. The greatly enlarged, winglike pectoral fins then spread out as the fish...

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The unique fishes called flying fish appear to soar above the water. But they do not actually fly by flapping wings, like birds do. Instead, they jump from the water and use their fins to glide through the air.

The fish that can "fly" through the air for long distances is called the flying fish. It takes to the air with two winglike fins that are attached to either side of its body. These are known as pectoral fins. They are really elastic membranes that, when spread, serve as "wings."